The field of the disclosure relates generally to rowing equipment, and more particularly to a sleeve and collar for a rowing oar.
At least some known boats include oars used by a rower to provide forward thrust to move the boat. For example, the oar acts as a lever that pivots around a fulcrum fixed to the boat as the rower moves the oar back and forth through a rowing motion. As least some known oars use an oarlock as the fulcrum. For example, the oar is inserted through the oarlock, and the oarlock pivots on a vertical pin coupled to the boat. At least some known oars include sleeves that are fixed to the oar to improve handling of the oar and/or to act as a replaceable wear surface for the oar at an oarlock contact area. At least some known sleeves are used with a collar that couples around a portion of the sleeve and acts as a stop to prevent the oar from sliding completely through the oarlock.
At least some known collars can be selectively coupled to any of several locations on the sleeve, such that each location provides a correspondingly different mechanical gearing for the rowing motion. At least some rowers prefer to select a different mechanical gearing, and hence a different collar position, for different performance conditions. However, at least some known sleeves, such as but not limited to some two-piece molded thermoplastic sleeves installed on the oar with a bonding agent, tend to twist and/or bulge during installation. The twisting and/or bulging causes an oar blade pitch angle, determined by the interface between the oarlock and the sleeve at the oarlock contact area, to vary for different collar positions, adversely affecting the rower's performance.
Moreover, at least some known sleeves require a user to apply a tool, such as a screwdriver, to reposition the collar. The required use of the tool increases a complexity of changing the mechanical gearing, both on land and in the boat. At least some known sleeves at least partially address this concern by providing spacers that can be positioned on an outboard side of the collar. However, because the spacers move the oarlock contact area to a different position on the sleeve, the problem of varying blade pitch angle is not resolved.